Direct current commutating system



June 27, 1933. E 1,915,790

DIRECT CURRENT COMMUTATING SYSTEM Filed May- 51, 1930 Inventor Erwin Kern Attorney Patented June 27, 1933 NITED 1 STATES P ATE-NT entice nnwm KERN, or rwn'r'rme-nn, SWITZERLAND, .Assreiion "r AKri-nNensE-Lnscrmm BROWN novnnra 01 s., or 1211mm, swirzunrann, a JOINT-STOCK company or V "SWITZERLAND DIRECT CURRENT COMMUTACEING'SYSTEJVI Application filed May 31, 1930,8eria1 'Ho. 457,778; and-in Germany May '30, 1929,

(GRANTED uimnnencrren 14, ACT'OE.-MARGH2,"1927,35710. e. s)

This invention relates to improvements in devices. for commutating direct current ,in whichzthe operating voltage ill notbe limited by thevoltage of .each segmentof the usual type ofcommutator and, therefore, by the number of segments available.

Indirect current motors of the usual type, ..the:characteristics of the motor are determinediby the proportion of its several portions which cannot be usually modified as desired. To obtain diiierent characteristics, the position of the brushes on the commutator ence on electrical ormechanical values of the structure; Suchiadwstment of the brushes hasbeen found, heretofore, impossible to ob- 'tain because of the difliculties of commutation which could not be overcome. Another mea'ns'for obtaining the above result was the shifting the position ofthe field relative to the neutral line of the armature, as for instance, bythe variable excitation of a second I set of field coils which means were, however,

also unsuccessful because of commutation 'clifiiculties. I

If; however, commutation is providedffor bythe use of controlled electricvalves, such valves being conductive-in'only one direction, it is no -longer necessary that the portions oi the armaturewinding'be coinmutated when passing thru a field oi predetermined strength which is proportional to the current.

"as will be seen from the following.

Consequently, in a directcurrent motor having electric valve commutation,the neu tral line of the armature may be displaced as desiredprovided the field strength impressed on the armature is suificient to produce a re- :versa'l of current. The usual controlled electron dischargetubemay be used forsuch purposes without encountering anydifiiculties in operation butsuch tubes are impracticalfor many reasons inherent in the tube structure itself, chief of which is the limitation to small quantities of energy which may pass therethru. y

The above diiiiculties of tube operation are not present in'valves of other typessuch as ';grid controlled electric; current rectifiers of themetallic =vapor-type or such as theso commutatin'g direct current. Without regard called thyratrons whichare hot. cathode grid pable of controlling large .quantitiesof current. It is well knownthat .insuch tubes, however, although no current will flow ,as

long as the grid is at negative potential relative tothe'cathode, the .fioW of current once started cannot be interruptedby use of the grid. .ruptithe cu rent in the circuit by othermeans, may be varied either manually or in depen'd- It is, therefore, necessary to inter- :ch "as the introduction of alternating voltages of suitable magnitude, after which passage of current can be prevented by maintion, the source of current is connected tor two points of the armature through electric.

valvesand after a certain period of timez-is also connected totwo different points of the armature through another set of valves.

The current isthen extinguishedin the circuit connected with thelirst two points by making the gr1ds ofthe valves negative and thereupon impressing,thereon anvalternating voltage of such magnitude'as to interrupt the current "in "the circuit... Thesource is theniconnected to a third pair of armature po1nts and the above cycle of operationais' repeated, The current taken oil atdifier'ent points of-the armature by the above method is variable but the total current is substantially constant.

Itis therefore, among the objects'of-"the present invention to provide'a device for to "the-number of segments oftheusual type of commutatorsand their voltage as was the case heretofore.

Anotherobject ofthe present invention g-is to provide a device forcomm'utating direct current which device will employ electric valves to obtain the desired results. V

Anotherobjectof the inventionis'to provide a device for coinmutating direct ourrent in which mercury vapor arc devicesfcontrolled by'grids or so -called thyratrons are used. 1

Another object of the invention is to provide a device for commutating direct current in which'conductors are connected to the armature windings of a direct current motor and an alternating current is superimposed on such conductors to cause the direct current flowing therein to pass, periodically, through zero. Y

Another object of the invention is to provide a device for com mutating direct current in which the characteristics of the motor, as determined by the proportions of the different portions thereof, may be .varied manually or in dependence on electrical or mechanical values thereof.

Another object of the invention is to providea device for commutating direct current in which the characteristics of the structure are variable by means of control grids rent in which the characteristics thereof are changed by addition of one or more field windings'e'zcited in dependence on electrical or mechanical values of the same or of adjacent structures.

Objects and advantages, other than those above set forth, will be apparent from the following description when read in connecwhich tion with the accompanying drawing in Figure 1 diagrammatically illustrates one embodiment of the present invention and Fig.2 diagrammatically illustrates a modified embodiment of the invention in which only such portions of Fig. 1 as are essential to the understanding of the modification are shown. 7 r g I Referring more particularly to the drawing by characters of reference the reference numerals .3 and 4 designate the several porusual for controlling direct current motors.

The armaturewinding 6 is shown as being divided into only '6 sections, although it is evident .that it may be dividedinto any number of sections, which sections are connected at point I, point II, point III, point TV,

point V, and point VI. It is evidentthat the motor maysalso be constructed with a fixed armature and arotating field, the por-' tion ,of the structure to be described being correspondingly movable or stationary so as to maintain the mechanical relations there- A plurality of slip rings, 11,12, 13 and l are mounted on the shaft (not shown) of the armature 6 and areconnected through brushes with the secondary windings of transformers 16 and 17, the primary windings of which are connected with and supplied with alternating current of suitable frequency from an alternatorlS, also mounted on the shaft of the motor. The primary windings of the transformers 16 and '17 are such position as to permit rotation of brushes as at 23 and 24, by the motor shaft, on the commutaton' The commutator segment 21 is connected through a resistance 28 to the positive side of a battery 25 and withfthe.

slip rings 13 and 14: and the segment 22 thereof is connected through a resistance 26 and to the negative side of a battery 27 and with the secondary winding of a transformer 17 and, therefore, with the slip rings 11 and '12.

The Various points of connection designated by the roman numerals, of the armature winding are connected with pairs .of vapor or gas filled electric valves as shown at 31, 32,33 and 34 andthe grids of the valves are connected through resistance 36 "with brushes 23, 24 etc, rotating on thecommutator. It will be seen that each of the armture winding connection points is connected with one pair of valves which areso con nected that one valve of, the pair functions to allow current'to 'flow only into the arms;- ture and the other valve of the pair functions to allow current to flow only out of the armature windings.-

In operation, the device passes througha constantly recurring cycle of operations, to be now particularly described in the rotation of the armature winding, which brings the connection points thereof to the same point successively with relation to the field.

When the entire device is in the. position shown in the drawing, the motor may be started by; closing of the switch 8 and regulated by adjustment of the rheostat 9 as "is' usual. A circuit is complete from the source of direct. current 7 through i the secondary winding of the transformer 17, over the slip .ring 13, the valve 31,: to the point VI of the armature windingv 6, through the winding 6 inboth directions to the point III, through valve 32 to slip ring 11, through. transformer secondary winding 16, field windings 4and d 3, rheostat 9, and switch 8 to the line 7. The grids of the valves 31 and 32 are supplied withv a positive bias. from the battery 25 through the commutator segment 21 and brush 23 in contact therewith at the positionshown in the drawing. All of the other valve grids are given a negative bias from the batsegment 22 and the brushes resting thereon,

sidered, the grids of valves 31 and 32 vare line T through the secondary windings of the igerag'zeo thereby preventing'the flowof'current tame several negatively biased tubes: or valves.

' During the nextmoment of operation the armature and the commutator will have rotated" sufli'cientlyto bring point V midway between its location shown in the drawing and that shown for point VI and the brushes 23 and 24 will havebeeniso rotated as to be both in contact with the segment 21'. A circuit isithen'completed'from the direct current supply line 7 to the secondary winding of the transformer'17, over the sliprings 13 and 14', through valves 31 and 33, to the armature winding connection points V and VI, through'winding 6 tothe points II and III, through valves 32 and 34 to the slip rings 11 and 12, through the secondary winding ofthe transformer 16, fields 4 and 3, rheostat 9 and switch: 8 to the line 7. The grids of the Valves 31,. 32,33 and 3 1 are supplied with a positive bias from the battery 25' through the commutator segment 21 and the brushes 23 and 24 contacting therewith. All of the other valve grids are negative as above described. i

During the next momentof rotation of the armature and of thebrushes,"point V will have been brought to the position shown in the drawing for point VI and brush 23 will have rotated sufliciently'to contact with commutator segment 22 on which a negative bias is impressed fromthe battery 27; A circuit is completed from the direct current supply transformer 17, the slip ring 14, the valve 33 to point V,through the winding 6-in both directions to the point II thereof, through the valve 34 over the slip ring 12, through the secondary of the transformer 16, fields 4 and 3 rheostat 9 and switch 8 to the supply line 7 The grids of valves 33 and 34 have a positive bias impressed thereon and all of the other valve grids are negative as respects the cathode as above described. r

a It willbe seen that in the first position conmotive forces produced in the two circuits by the armature. Once interrupted the current in the first circuit cannot pick up again until the grids of valves 31 and 32 are again positive. 1 a

I Two embodiments of means are shown by which the neutral line of the armature' winding may bemanually or automatically displaced in dependence on current, voltage or load or anyother desired value with respect to. the axis ofthe field windingL As shown a in Fig. 1,a grid control commutator; is provided with a jointed lever 35 by which: the

commutator may be manuallyshif-ted and the lever 35 is also provided with a portion forming a core for a coil 37 whichis shown as connected across a shunt in circuit with the direct current line 7 but which may be connected with any portion of the structure whereby thecoilwill be energized by a pre-" determined range of values. 7

F ig; 2 illustrates theuse of a second or additional set of field windings 41 and 42 which are displaced: relative to themain field winding 3 and 4 and which are supplied in dependenceon the, current or voltage of themotor with electrical values other than those of the main field winding. and which may beeither manually or automatically regulated to obtain valuesdilferent from those present in the windings 3 and 1. V

1 Although but two embodiments ofthe present invention have been illustrated and described, it will be apparent to those skilled in the art that various changesand modifications may be made therein without departing from the spirit of the-invention or from the scope of the appended claims.

The invention claimed is v V 1. In a directcurrent motor, an armature winding divided into aplurality of sections, series and'shunt connected field windings arranged adjacent said armature winding, electric valvesconnected with the sections of said armature wlnd ng, a source of alternatingcurrent, a plurality of slip rings connected between said valves and said source of alternating current, transformers connecting said slip rings and said source of alternating current,a source of direct current connected with" the secondary w ndings of said transformers, a substantially stationary commutator divided into segments sources of direct current ,ofdili'erent pol-arityconnected with the segments of said commutator, and brushes rotative into contact with the said segments of said commutator and connected'wlth said valves tompress a'b as on th-e'grldsthereof tothereby cause the angular displacement of the neutral line of the armature winding rela-' tive to the field windings in dependence upon too the movements of connections of said brushes 1 with the said segments and in dependence upon the relative excitations of the said field windings. I

'2.Inadirect current motor," an armature winding divided into'a plurality of sections, series andshunt connected field windings arranged adjacent said armature winding, electric valves connected with the sections of said armaturewinding, a source of alternating current, a plurality of slip rings connected between said valves and said source of alternating current,fa source of'direct current connected with said slip rings, andmean's-for variably displacing the neutral line ofthe Comprising an armature winding divided in- 7 armature winding with respect to said field windings in dependence upon the excitation.

comprising an armature winding divided into sections, and-a field winding arranged in-op-T erative relation with said armature winding, I

of the said shunt windin'grelativextothe excitations of the said series winding to adjust the characteristics of the motor within wide limits. V

3. In a direct current motor, an armature winding divided into a plurality of sections,

field windings arranged adjacent saidarmature winding, electric valves connected with the sections of said armature winding, a

source of alternating current, a plurality of slip rings connected between said valves and said source of alternating. current, a source ofdirect current connected with said slip rings, and means for automatically displac-" 4. In combination with an electric motor to a plurality of sections, and a plurality of field windings connected in a series and in shunt respectively with said armature winding, of a source of direct current for operating said motor, a source of alternating cur-' rent superimposed upon the said direct current, a plurality of electric Valves connected with said sourcesand with said windings and disposed to control the flow of said currents sequentially therethrough to said windings, means operative to control the said flow of said currents through the said valves, and

means operative'to afl'ect the operation of the first said means in such manner as to vary the periods of said sequential flow of said currents throughsaid valves to said windings to thereby adjust the operating characteristics of the said armature winding with respect to the operating characteristics'of the of said series connected winding.

said field windings in dependence upon the degree of excitation of said shunt connected 5. In combination with an electric motor comprising an armature winding divided into a plurality of sections, and compound field wlndmgs arranged in operative relation with said armature windlng, of a source of direct currentfor operatingsaid motor,

a source of alternating current superimposed upon the sald direct current, a plural ty of electric valves connected with said sources and withsaid windings and disposed to control the. flow of said currents sequentially therethrough tothe said windings, means adjustable to a'plurality of positions and adjust the operating characteristics of the said-sections of the said armature winding the said flow of said direct of a source of direct currentfor operating the said motor, a plurality of electric valves s connected with said source and with the said windings, the said valves being disposed to control thefiow of saidcurrent therethrough to the said windings, a source. of alternating current, means operative to superimpose the said alternating current upon said direct current toaifectthe said-flow of said .direct'current through the said'valves, control Qmeam operativeto adjust the operating characteristics of the said sections of the-said armaturewinding relative to the operating characteristics of the said field winding, thelast said means being adjustable independence upon said valves. e

7. In combination withanelectric motor comprising an armature winding divided into i a plurality of sections, anda field windingearranged in operative relation to said "armavalves disposedto connect the said sourceof current through current with the said-windings, a source of alternating current, means operative to superimpose the said alternating current upon the-said direct current and operative to affect the flow of saiddirect'current to said 3 windings by way of said valves, control means operative to adjust the'said flow of said currents by way of said'valves, the last said to the said valves; 7 v. V 8. Incornbination with an electric motor comprising an armature winding divided into I a plurality of sections, a series connected field winding, and a shunt connected field winding arranged'in operative relation to the said armature winding, a source of direct current for operating the said motor, a plurality of electric valves continuously connected with said source and with the said windin to control the flow-of said current sequential y through-said valves to said windings, a source of.- alternating current, a plurality'of trans- I formers connected withsaid source of alternating current; and, having a winding connectedj: 1n circuit with the said source of direct current whereby the said source of alternating current issuperimpo'sed upon the said, direct current and operative thereby to? affectthe flow of said direct current through f 1 the said valves .to the said.windings,va. cont'rol electrode for each of saidvalves, a plurality of auxiliary sources-of direct current,

means for con'nectingeach of said auxiliary sources with each of said control electrodes to affect the said flow of current sequentially through the said valves to the said windings, and means operative to a plurality of positions to ailect the first said means to vary the said connections of the said auxiliary sources to thereby vary the periods of the sequential flow of current through said valve whereby the operating characteristics of the said armature winding is adjusted relative to the operating characteristics of the said field winding in dependence upon the degreevof excitation of said series connected winding relative to the degree of excitation of said shunt connected winding. 7

9. In combination with an electric motor comprising an armature Winding divided into sections, a series connected field winding, and a shunt connected field winding arranged in operative relation with the said armature winding, a source of direct current for operating the said motor, a plurality of electric valves continuously connected ivith said source of current and with the said sections of the said armature winding and operable to control the flow of said current sequentially through said valves and through said Windings, a source of alternating current, means operative to effect superimposition of said alternating current upon said direct current,

the said alternating current being effective to affect the said flow of said direct current through said valves to the said windings, each said valve including means operative to affect the flow of said currents sequentially through saidvalves to said windings, a commutator comprising a plurality of segments, a

plurality of auxiliary sources of current connected with the said segments, a plurality of brushes rotative into contact with said segments and operative to connect the saidauxiliary sources of current sequentially with the said means, and'means operative to rotate the said commutator to vary the periods of connections of said-auxiliary sources with the first said means to thereby adjust the opcrating characteristics of said armature windmg relative to the operating characteristics of said field windings in dependence upon 1930. V ERWIN KERN. 

